Living systematic review: new inputs and challenges.

This is the second article from a collaborative methodological series of biostatistics and clinical epidemiology narrative reviews. This review aims to describe living systematic reviews relevance, the considerations that should be taken when producing one, and the challenges proper of this type of review. The living systematic review is a continuous update that maintains a systematic reviews rigor and methodological quality. The living format is appropriate when the review aims to answer a priority question in terms of health decision-making, the existent certainty of the evidence for this question is low or very low, and new evidence will likely appear soon. To carry out a successful living systematic review, researchers should consider different things, such as: having a continuous and automated search, having update criteria, evaluating how to update the meta-analysis and how to perform the editorial process, and publishing in a friendly format, among others. As living systematic reviews are a new proposal, they will likely change in the future to improve their performance, so we will have to keep an eye on its future updates.